peridigm_strength.hpp

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#pragma once
 
#include "utils_math.hpp"
 
namespace netdem {
 
class PeriDigmStrength {
public:
  // particle breakage strength
  double ref_size = 1.5e-3;
  double ref_energy_release_rate = 60.0;
 
  double weibull_modulus = 3.1;  // McDowell 2002
  double weibull_coef_a = -0.76; // Hanley et al 2015
  double weibull_coef_b = 1.13;  // Hanley et al 2015
 
  double min_breakable_size = 0.02;
 
  // note that the critical energy release rate is calculated with pre-assuming
  // that the pd horizon is a same prescribed times of particle size divided by
  // a same prescribed mesh resolution. Please refer to Zhu & Zhao, 2019 CMAME
  // for  detials
  double GetEnergyReleaseRate(double size) {
    double strength_ratio =
        (double(rand()) / double(RAND_MAX) - weibull_coef_b) / weibull_coef_a;
 
    return ref_energy_release_rate * strength_ratio * strength_ratio *
           pow(size / ref_size, -6.0 / weibull_modulus + 1.0);
  }
 
  double GetEnergyReleaseRate(double size, double percentile) {
    double strength_ratio = (percentile - weibull_coef_b) / weibull_coef_a;
 
    return ref_energy_release_rate * strength_ratio * strength_ratio *
           pow(size / ref_size, -6.0 / weibull_modulus + 1.0);
  }
};
 
} // namespace netdem